Do you reach for the salt shaker at a restaurant while your guest shuns it, claiming a blood pressure problem? Think again – according to recent studies, healthy individuals with normal blood pressure should avoid a sodium-saturated diet. You might ask, “What is a sodium-saturated diet? Answer: it is a diet high in sodium relative to potassium. Both commonly come as salts of chlorine: sodium chloride (NaCl) and potassium (KCl). Both are present in bodily fluids.
An Institute of Medicine study IOM study, published last year, reviewed data from more than 12,000 American adults; it was looking for risk factors for death from heart disease. The investigators found that while a diet high in sodium increases ones risk, of more importance is the ratio of sodium to potassium in one’s diet: sodium increases heart disease risk while potassium lowers it. According to the IOM study, “No one is immune to the adverse health effects of excessive sodium intake.”
When individuals whose meals contained less sodium than potassium were compared with those whose diets had a high sodium-to-potassium ratio, the latter were nearly 50% more likely to die from any cause and more than twice as likely to die from ischemic heart disease during a follow-up period (average: 14.8 years).
A high sodium diet increases blood pressure and increases the risk of chronic hypertension; sodium reduces the elasticity of the arteries and blocks nitric oxide, which relaxes arteries. A chronically-elevated blood pressure increased the risk of cardiovascular disease: heart attacks and strokes. Conversely, potassium activates nitric oxide, which relaxes the arteries and lowers the risk of hypertension.
Another study, which was published earlier this year in the Archives of Internal Medicine by the Centers for Disease Control and prevention (CDC), also evaluated the sodium-potassium ratio in one’s diet. “We controlled for all the major cardiovascular risk factors and still found an association between the sodium-potassium ratio and deaths from heart disease,” noted Dr. Elena V. Kuklina, a nutritional epidemiologist at the CDC and an author of the study. She added, “With age, the risk of high blood pressure increases. The lifetime risk in this country is 90%. If you live long enough, you’re at risk.”
Approximately 90% of the sodium in the American diet comes from salt, three-fourths of which is consumed in processed and restaurant foods. Salt added in home cooking and at the table accounts for only a minor proportion of sodium intake. Another source of sodium is in water softeners, which exchange hard minerals with sodium. Many are not aware that water softeners can be charged with potassium chloride rather than sodium chloride. The potassium salts are more expensive; however, the health benefit makes them worth the extra cost. Also of note, potassium-softened water is healthy for your house plants, which shrivel and die if watered with sodium-softened water.
The body’s daily requirement for sodium is extremely low, about 220 milligrams; however, the average American consumes more than 3,400 milligrams per day. The current Dietary Guidelines for Americans recommend a maximum of 2,300 milligrams (about a teaspoon of salt) for individuals over the age of two; however, only 1,500 milligrams for the 70% of adults at high risk of sodium-induced illness: individuals older than 50, all African-Americans (who are more susceptible to hypertension), all hypertensive individuals, diabetics, and those with chronic kidney disease.
Sodium intake by Americans has increased in recent decades, despite widespread efforts to urge them to cut back on sodium. The sodium derives from an increased consumption of restaurant and processed foods; the sodium is added as a preservative and flavor-enhancer. The flavor-enhancer monosodium glutamate (MSG) is another source of sodium. The Food and Drug Administration (FDA) categorizes sodium as “generally recognized as safe” (GRAS); thus, there is no limit to the amount food producers can use in a product.
Another downside of processed foods (i.e., tomatoes and potatoes) is that the process not only adds sodium to the food but also results in a depletion of the natural potassium contained in the food. The result: a sodium-saturated product.
The widespread use of sodium in foods prepared outside the home has created an American preference for a salty taste, a preference that can be reversed with no loss of consumer pleasure if done slowly, noted Dr. Thomas A. Farley, commissioner of New York City’s Department of Health and Mental Hygiene. His department is leading a national effort, which began in 2008 to urge food producers and restaurants to gradually reduce the salt in their products. To date, 28 national food companies, retailers, and supermarket chains, including Delhaize America, Kraft, Subway, and Target, have made a commitment to the National Salt Reduction Initiative to cut sodium in their products by an average of 25% by 2014.
